A number of patent references relate to boom structures. In both U.S. Pat. No. 2,508,835 to Moon, et al. and U.S. Pat. No. 2,331,559 to McEwan, a telescoping boom structure is disclosed. Cables extend from the tops of the lower boom member about pulleys at the bottom of the extendable boom member, back around pulleys positioned at the tops of the lower boom members, and back to a winch. In U.S. Pat. No. 3,423,890 to Leigh, a structure is described wherein a frame having rollers is provided about a circular inner boom member which will prevent the rotation of the circular boom member within an outer square boom member. In U.S. Pat. No. 2,515,833 to Mueller and U.S. Pat. No. 2,593,764 to Kaunitz, portable hoisting devices are shown which are attachable to moving vehicles.